A horrible boss who has no idea how to run a buisness. (S)He has the same lame motivational phrases which become meaningless after hearing them day in and out. Also, you totally hate his/her guts for being a total tight-wad.

A supervisor who is too lazy to do his own work so he passes it down to everybody else. An incompetent piece of shit who only gets promoted because he cornholes the boss. He would otherwise be a total melvin if he wasn't a supervisor.

God dammit! That fucking Lumbergh is making me come in this weekend to clean up his mess.

A person with an incredibly repulsive personality. So much so that anyone who has sex with that person will forever be tainted e.g. friends will lose respect for that person, and potential or current partners will no longer be attracted to that person, once they find out that they have had sex with a Lumberg.

In the 1999 movie Office Space, Peter (Ron Livingston) believes that his girlfriend Joanna (Jennifer Anniston) has had sex with his boss, Bill Lumbergh (Gary Cole). Once this information becomes known, he no longer wants anything to do with Joanna and is tormented by the thought of his girlfriend having sex with Lumbergh.

also,

Friend A: "That girl is such a Lumbergh!"

Friend B: "Yeah, this guy I know had sex with her. I can't even look him in the eye anymore."